Exchange had a population of just 20,000 in 1951, the lowest of any ward. By 1971 it had more than halfed. So it's population was essentially people who 'lived above their shops' and other assorted residencies.
Thought so, yeah.
Long period with no re-warding; I think Birmingham may even have been re-warded twice in the same period (though it may have been just once. No, I think it was twice...)
The "building out" argument always did seem stronger for Glasgow than other places, 'though probably more important (more important than the fragmentation you're getting onto) would presumably be middle class people just leaving the city. Population of Glasgow dropped like a stone in the decades after the War.